Hughes v Metropolitan Ry [1877]

H leased houses to M.
H served on M notice to repair houses within 6 months.
If not complied with, M would forfeit lease.
Parties then began to negotiate over sale of lease.
H broke off negotiations shortly before notice due to
On expiry, claimed M had forfeited lease.
Lord Cairns in House of Lords:
If parties who have entered into terms with definite
legal results afterwards by their own act enter into negotiation which has the
effect of making one of the parties believe that the strict rights under the
contract will not be enforced, or will be suspended, then other party will not
be allowed to enforce those rights where it would be inequitable to do so
having regard to previous dealings between the parties.